A typical raster scanned printing system scans a laser beam along a succession of parallel rows on a workpiece, one row at a time, to form a pixel pattern representing a two-dimensional image. Scanning is done by an oscillating mirror. During one direction of an oscillation a single row is scanned. The mirror is then quickly returned to its original position to begin scanning the next row. An optical encoder may be used to gauge the angular position of the mirror, to aid placing the pixel marks at precise locations along each scan row.
The pixel mark may be formed using an ink coated foil that transfers a spot of ink onto the workpiece in response to receiving laser beam energy at a pixel site.